Re: [PATCH 2.6.11-rc2] ide: merge do_rw_taskfile() and flagged_taskfile()into do_taskfile()

[Tejun Heo]

Hello,

Bartlomiej Zolnierkiewicz wrote:
> On Sun, 6 Feb 2005 11:13:31 +0900, Tejun Heo <tj@xxxxxxxxxxx> wrote:
>
> > Hello, Bartlomiej.
>
>
> Hi,
>
>
> > This is a new version of ide_do_taskfile.patch.  Compared to the
> > original do_rw_task(), only one more 'if' is used in the hot path, so
> > I think the performance issue can be ignored now.  Also, there's no
> > userland visible change with this patch.  Everything should work just
> > as it did with do_rw_taskfile()/flagged_taskfile().
> >
> > do_taskfile() is different from do_rw_taskfile() in that
>
>
> Is there any gain in changing name to do_taskfile()?
>  

 Well, I was just thinking

 do_rw_taskfile + (do_)flagged_taskfile -> do_taskfile.

 If you like do_rw_taskfile better, I guess that's okay too. :-)

> > - It uses task->data_phase to determine whether it's a DMA command
> >   or not.
>
>
> this is user-space visible change
> (it is right thing to do, I just wanted to point the fact)

 Oops, I forgot that.  Still, it was kind of weird before.  If any of 
tf_{in|out}_flags is set, flagged_taskfile() is called and ->data_phase 
was used, but, if none of the flags was set, do_rw_taskfile() was called 
and the command is used to determine the same thing.  But, yeah, it's 
user-visible.

> > do_taskfile() is different from flagged_taskfile() in that
> >
> > - No (TASKFILE_MULTI_IN && !mult_count) check.  ide_taskfile_ioctl()
> >   checks the same thing, so it doesn't change anything.
>
>
> The check may be needed.  AFAIR drive->mult_count may change
> before our taskfile request is started.

 Okay, I'll resurrect that test.

> > - No task->tf_out_flags handling.  ide_end_drive_cmd() ignores it
> >   anyway, so, again, it doesn't change anything.
>
>
> I guess you mean ->tf_in_flags?

 Yes.

> > So, what do you think?
>
>
> This patch looks much better but could you move writing taskfile
> registers to separate helpers (one for non-flagged and one for flagged)?
>
> Probably splitting non-flagged taskfile load helper off do_rw_taskfile()
> should be done in separate patch.  We can then use this helper in
> ide-disk.c for __ide_do_rw_taskfile() (we can't do direct conversion
> to do_rw_taskfile() yet for various reasons).

 Sure, I'll do it now.

 Thanks.

--
tejun

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/